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Biomedical subjects

J B Graham

Publications and source records attributed to J B Graham.

At least 19 recordsLinked to original sources
PubMed1992

The effects of ultrasound-guided shock waves during early pregnancy in Sprague-Dawley rats.

Pregnancy is a contraindication to extracorporeal shock wave lithotripsy (ESWL) because of its possible harm to the embryo or fetus caused by shock waves or ionizing radiation. In this study timed-pregnant rats were subjected to shock waves early in gestation using a lithotriptor having ultrasound imaging. In a pilot group undergoing immediate laparotomy, it was determined to what extent the pelvic structures were effected. Then a test group was exposed to shock waves and carried to near term pregnancy along with an identical group of pregnant, sham procedure rats. A laparotomy all were inspected for fetal viability, fetal abnormalities, and maternal organ damage. Fetuses located nearest the focal area of maximum shock wave energy showed lower mean weight than controls. There was no recognizable gross or microscopic fetal damage.

Animals↗
PubMed1992

Digital image analysis of shark gills: modeling of oxygen transfer in the domain of time.

Digital radiographic imaging of blood circulation through leopard shark gills establishes a secondary lamellar transit time of 6.5 s. This duration, combined with estimates of cardiac output and hemoglobin-oxygen affinity, permits novel modeling of gill oxygen transfer in the time domain. The temporal model allows assessment of factors contributing to previously noted discrepancies between physiological and morphometric branchial oxygen conductance estimates. Lamellar transit time for shark blood is 20 times greater than human alveolar transit time, and thus correlates with a slower rate of hemoglobin-oxygen binding and a greater diffusion distance.

Animals↗
PubMed1991

Population genetics of the Malmö polymorphism of coagulation factor IX.

The distribution of 1,198 Malmö alleles was examined in 822 men from 16 indigenous populations and 188 women from 7 of the ethnic groups. Subjects were from several European countries, the Mediterranean, East Asia, and the USA (Anglo- and African-Americans). The frequencies of the rarer (Malmö B) allele were approximately equal across Europe, the highest frequencies (0.36) being in the French and Anglo-Americans; no population was observed with clearly the highest frequency. They diminished slightly at moderate distances from Europe (Tunisia, Ethiopia) and greatly at longer distances (East Asia and West Africa). In Orientals, the frequencies ranged from 0.07 (East Indians) to 0.03 (the Chinese) and from 0.0 to 0.15 in African-Americans. Assuming selective neutrality, the data are consistent with the European origin of the 'B' allele when the population was small and outward spread.

Africa, Northern↗
PubMed1991

The varying frequencies of five DNA polymorphisms of X-linked coagulant factor IX in eight ethnic groups.

Five RFLPS of X-linked coagulation factor IX were evaluated in more than 500 normal persons (723-804 X chromosomes) of both sexes who belonged to eight ethnic groups: Anglo-Americans, Basques, Swedes, African-Americans, East Africans, East Indians, Chinese, and Malays. The polymorphisms, 5' to 3', were BamHI, XmnI, TaqI, MnlI, and HhaI. A PCR procedure was developed for three previously described RFLPs-XmnI, TaqI, and MnlI; a PCRP procedure was developed for BamHI, and a PCRP which had been described by others was used for HhaI. Europeans were the most polymorphic, African-Americans and East Africans were intermediate, and Orientals were the least polymorphic. Extragenic 3' HhaI was highly polymorphic in most groups, and extragenic 5' BamHI was polymorphic only in persons with African ancestry. Two major haplotypes predominated among 247 men, and the expected and observed heterozygosities were concordant among women. Allelic association was very strong between the three intragenic PCRPs; it was present but weak between 5' extragenic BamHI and XmnI. No association was found between 3' extragenic HhaI and MnlI.

Asian People↗
PubMed1990

The utility of a HindIII polymorphism of factor VIII examined by rapid DNA analysis.

A previously described HindIII restriction fragment length polymorphism (RFLP) of factor VIII (FVIII) has its polymorphic site in the unsequenced nineteenth intron. We have located the polymorphic site, as well as an invariant site, by amplifying and sequencing IVS 19 using the polymerase chain reaction (PCR). The oligonucleotide primers were synthesized from known FVIII sequence on either side of the 19-20 splice junction. The amplified product was cloned into a plasmid and sequenced by the dideoxy chain termination method. The polymorphic HindIII site was 103 bp and the invariant site 184 bp from the 3' end of the nineteenth exon. The frequency of the polymorphism was determined in 457 subjects (643 chromosomes) of seven ethnic groups on whom frequency of the BclI RFLP of IVS 18 was also assessed. The HindIII site is highly polymorphic in all groups, approximately 0.25:0.75, the expected heterozygosity averaging 37.6%, and the observed number of heterozygotes did not differ significantly from expectation. The (+):(-) allelic ratio is similar in all groups, except African-Americans in whom it is reversed. Strong allelic association (linkage disequilibrium) is present between the HindIII polymorphism of IVS 19 and the BclI polymorphism of IVS 18.

Alleles↗
PubMed1989

Lithotripsy for bile duct stones.

Fragmentation of bile duct stones by mechanical, electrohydraulic, and laser intraluminal lithotripsy has greatly facilitated the ability to remove stones that are otherwise difficult to remove by standard manipulative techniques. Even these approaches fail when stones lack access or are impacted within the biliary tree. Extracorporeal shock-wave lithotripsy (ESWL) was evaluated in the United States in a multicenter trial with 56 patients. Stone fragmentation occurred in 91 percent of patients and duct clearance in 79 percent. Adjunctive procedures were used in 54 percent. Two ESWL treatments were required for fragmentation in 28 percent. Complications were mild and relatively infrequent. Hemobilia (8 percent), gross hematuria (6 percent), and biliary sepsis (4 percent) occurred less frequently than expected. There were no deaths during the 1 to 31 days of hospitalization (mean 9 days). We conclude that ESWL is a safe and effective adjunct to the treatment of difficult-to-remove bile duct stones under the conditions observed in this trial.

Bile Duct Diseases↗
PubMed1989

Hemophilia: state of the art of hematologic care 1988.

Since 1982, when the World Federation of Hemophilia first published a document on the state of the art of hemophilia diagnosis and care, there have been lights and shadows in this field. Although the widespread infection of hemophiliacs with the human immunodeficiency virus (HIV) contaminating clotting factor concentrates is still a threatening and formidable shadow, the gloomy picture brought about by the AIDS epidemic is partially lightened by spectacular improvements in therapy and diagnosis. Carrier detection and first-trimester prenatal diagnosis can now be performed accurately in most kindreds by analysis of DNA of the factor VIII or IX genes. An important step forward towards the elimination of the risk of blood-borne infections transmitted by plasma products was recently made through the application of virucidal methods to clotting factor concentrates. Since HIV appears more vulnerable to such methods than the hepatitis viruses, currently available concentrates can be considered substantially free from the risk of transmitting HIV infection. Even though transmission of hepatitis is much reduced but not totally abolished, virucidal methods are continuously being improved, so that it can be foreseen that concentrates will become safer and safer. Finally, factor VIII produced by recombinant DNA technology is undergoing the first clinical trials in hemophiliacs. Hopefully, it will free from the risk of transmitting infections and will be available in sufficiently large amounts to meet the need of hemophiliacs worldwide. In 1982, the World Federation of Hemophilia published a message on the status of diagnosis and treatment of hemophilia. Since then, hemophilia care has been complicated by widespread infection of hemophiliacs with human immunodeficiency virus (HIV).(ABSTRACT TRUNCATED AT 250 WORDS)

Hematology↗
PubMed1989

The Malmö polymorphism of factor IX: establishing the genotypes by rapid analysis of DNA.

A DNA polymorphism in the coding region of coagulation factor IX--potentially valuable for carrier detection, prenatal diagnosis, and population studies--was described in 1985. It had been discovered with monoclonal antibodies that distinguish between threonine and alanine as the 148th residue of the peptide. Its use as a diagnostic tool has been limited because threonine-containing factor IX (Malmö A) is dominant to alanine-containing factor IX (Malmö B) in immunoassays of plasma; therefore, detection of Malmö heterozygotes is not possible in all instances. A DNA method for recognizing all heterozygotes has been developed, but it also has limitations. We report the development of another DNA procedure based on amplification of the relevant DNA with the polymerase chain reaction (PCR). This method is quick, avoids the use of isotopes and x-ray film, and specifically identifies all the Malmö genotypes: hemizygotes, homozygotes, and heterozygotes. The procedure can be performed satisfactorily on small samples of blood (less than 1 mL) as suggested by Kogan et al (N Engl J Med 317:985, 1987). The method described is applicable to any genetic polymorphism that overlaps a restriction enzyme recognition site.

Base Sequence↗